Power receiving apparatus, power transmission apparatus, control method, and non-transitory computer-readable storage medium

ABSTRACT

A power receiving apparatus, which has a first communication function and a second communication function, controls the first communication function to receive a first signal including information representing whether a power transmission apparatus can execute control communication using a second method, controls, based on the information representing that the power transmission apparatus can execute the control communication using the second method, the first communication function to transmit, to the power transmission apparatus, a second signal to request identification information of the power transmission apparatus for the communication of the second method and receive the identification information from the power transmission apparatus, and determines which one of the first communication function and a second communication function should be used for the control communication, based on the first signal and whether the identification information is received.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a control communication technique inwireless power transmission.

Description of the Related Art

Technological development of a wireless power transmission systemincluding a power transmission apparatus and a power receiving apparatushas been widely conducted. Japanese Patent Laid-Open No. 2012-217224describes a method of performing transmission/reception of controlsignals used at the time of power transmission/reception by so-calledout-band communication using frequencies, coils, and antennas which aredifferent from those used for the power transmission/reception in apower transmission system.

In a standard (WPC standard) established by WPC (Wireless PowerConsortium) that is the standardization organization of wireless powertransmission standard, power transmission/reception and controlcommunication therefor are performed by magnetic induction. In addition,a power transmission apparatus and a power receiving apparatus, whichcomply with the current WPC standard, perform control communicationusing the same frequency as the frequency used in powertransmission/reception. The control communication is so-called in-bandcommunication performed via coils used in power transmission/reception.Note that a communication range in which errorless communication can beperformed in in-band communication is narrower than the communicationrange of out-band communication.

Considering a power transmission apparatus and a power receivingapparatus each capable of executing both in-band communication andout-band communication, appropriate control communication in the powertransmission apparatus and the power receiving apparatus has not beenexamined.

SUMMARY OF THE INVENTION

The present disclosure provides an appropriate communication controltechnique in a power receiving apparatus and a power transmissionapparatus each capable of executing both in-band communication andout-band communication.

According to one aspect of the present disclosure, there is provided apower receiving apparatus comprising: a power receiving unit configuredto wirelessly receive a power from a power transmission apparatus; afirst communication unit configured to perform communication of a firstmethod using a first frequency to be used for power transmission; asecond communication unit configured to perform communication of asecond method using a second frequency different from the firstfrequency; and a control unit configured to control the firstcommunication unit and the second communication unit to perform controlcommunication for the power transmission, wherein the control unitcontrols the first communication unit to receive a first signalincluding information representing whether the power transmissionapparatus can execute the control communication by the communication ofthe second method, controls, based on that the information included inthe first signal received by the first communication unit representsthat the power transmission apparatus can execute the controlcommunication by the communication of the second method, the firstcommunication unit to transmit, to the power transmission apparatus, asecond signal to request identification information of the powertransmission apparatus for the communication of the second method andreceive the identification information from the power transmissionapparatus, and determines which one of the first communication unit andthe second communication unit should be used for the controlcommunication, based on the first signal received by the firstcommunication unit and whether the identification information isreceived by the first communication unit.

According to another aspect of the present disclosure, there is provideda power transmission apparatus comprising: a power transmission unitconfigured to wirelessly transmit a power to a power receivingapparatus; a first communication unit configured to performcommunication of a first method using a first frequency to be used forpower transmission; a second communication unit configured to performcommunication of a second method using a second frequency different fromthe first frequency; and a control unit configured to control the firstcommunication unit and the second communication unit to perform controlcommunication for the power transmission, wherein the control unitcontrols the first communication unit to receive a first signalincluding information representing whether the power receiving apparatuscan execute the control communication by the communication of the secondmethod, and determines which one of the first communication unit and thesecond communication unit should be used for the control communication,based on the information included in the first signal received by thefirst communication unit.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the disclosure, andtogether with the description, serve to explain the principles of thedisclosure.

FIG. 1 is a block diagram showing an example of the arrangement of awireless power transmission system;

FIG. 2 is a block diagram showing an example of the arrangement of apower transmission apparatus;

FIG. 3 is a block diagram showing an example of the arrangement of apower receiving apparatus;

FIGS. 4A and 4B illustrate a flowchart showing an example of theprocedure of processing of the power transmission apparatus;

FIGS. 5A and 5B are a flowchart showing an example of the procedure ofprocessing of the power receiving apparatus;

FIG. 6 is an operation sequence chart of the wireless power transmissionsystem;

FIG. 7 is a view showing the structure of a Configuration Packet; and

FIG. 8 is a view showing the structure of a Power Transmitter CapabilityPacket.

DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment(s) of the present disclosure will now bedescribed in detail with reference to the drawings. It should be notedthat the relative arrangement of the components, the numericalexpressions and numerical values set forth in these embodiments do notlimit the scope of the present disclosure unless it is specificallystated otherwise.

(System Arrangement)

FIG. 1 shows a wireless charge system according to this embodiment. Thewireless charge system includes power transmission apparatuses (a firstpower transmission apparatus 101 and a second power transmissionapparatus 102) and power receiving apparatuses (a first power receivingapparatus 111 and a second power receiving apparatus 112). Note that thefirst power transmission apparatus 101 and the first power receivingapparatus 111 will sometimes be referred to as “TX1” and “RX1”,respectively, and similarly, the second power transmission apparatus 102and the second power receiving apparatus 112 will sometimes be referredto as “TX2” and “RX2”, respectively, hereinafter. Note that each of thepower transmission apparatuses and the power receiving apparatuses has acommunication function by Bluetooth® Low Energy (BLE). Additionally, asan example, other apparatuses (a first communication apparatus 121 and asecond communication apparatus 122) each of which has the communicationfunction by the BLE but not the function of wireless power transmissionexist on the periphery of the wireless charge system. Note that acommunication unit (a unit formed by an antenna, a communicationcircuit, and the like) of the BLE will sometimes be referred to as “BLE”hereinafter.

Here, as shown in FIG. 1, each of the TX1 and the TX2 functions as aCentral of the BLE, and each of the RX1 and the RX2 functions as aPeripheral of the BLE. In addition, the first communication apparatus121 functions as a Central, and the second communication apparatus 122functions as a Peripheral. Note that the “Central” represents a controlstation of the BLE, and the “Peripheral” represents a terminal stationof the BLE. A Central of the BLE performs communication with aPeripheral of the BLE but not communication with another Central. Inaddition, a Peripheral of the BLE performs communication with a Centralof the BLE but not communication with another Peripheral. That is, inthe BLE, communication between Centrals or between Peripherals is notperformed. In addition, a Central can be in a connected state(CONNECT_State of the BLE) with a plurality of Peripherals and cantransmit/receive data to/from a plurality of Peripherals. On the otherhand, a Peripheral can be in a connected state with only one Central andcannot communicate with a plurality of Centrals in parallel.

In FIG. 1, when viewed from the TX1, the RX1 is located within the powertransmission/reception range, but the RX2 is not located within thepower transmission/reception range. Hence, the TX1 performs wirelesspower transmission only to the RX1 but not power transmission to theRX2.

In this case, if the TX1 should perform control communication byout-band communication using the BLE and transmit power to the RX1, theBLE (Central) of the TX1 needs to be in the connected state with atleast the BLE (Peripheral) of the RX1. Since a Central of the BLE cansimultaneously be in the connected state with a plurality ofPeripherals, as described above, the BLE (Central) of the TX1 may be inthe connected state not only with the RX1 but also with the RX2 and thesecond communication apparatus 122, which function as the Peripherals.Similarly, the BLE (Central) of the TX2 may be in the connected statewith the RX1 and the second communication apparatus 122 as long as it isin the connected state with the BLE (Peripheral) of the RX2.

On the other hand, the BLE (Peripheral) of the RX1 can be connected withonly one Central. For this reason, to perform control communication forpower transmission between the TX1 and the RX1 by the BLE, the BLE(Peripheral) of the RX1 needs to be in the connected state only with theBLE (Central) of the TX1. This is because when the BLE (Peripheral) ofthe RX1 is in the connected state with another BLE (Central) such as theTX2 or the first communication apparatus 121, control communication withthe BLE (Central) of the TX1 cannot be performed. Similarly, to performcontrol communication for power transmission between the TX2 and the RX2by the BLE, the BLE (Peripheral) of the RX2 needs to be in the connectedstate only with the BLE (Central) of the TX2. Hence, the BLE(Peripheral) of the RX2 should not be in the connected state withanother BLE (Central) such as the TX1 or the first communicationapparatus 121.

As described above, the control communication should be performedbetween a power transmission apparatus and a power receiving apparatus(for example, the TX1 and the RX1) for which powertransmission/reception is to be executed. However, when thecommunication range of out-band communication is wider than thecommunication range of in-band communication, the power transmissionapparatus and the power receiving apparatus sometimes establishconnection for out-band communication with an apparatus that is not thepower transmission/reception target. Such establishment of connectionfor out-band communication with an apparatus that is not the powertransmission/reception target will be referred to as cross connection.For example, a state in which the RX1 is BLE-connected with the TX2 orthe first communication apparatus 121 in FIG. 1 is the cross connection.

Referring to FIG. 1, when using the BLE (out-band communication) ascontrol communication, if there is no proof for BLE connection with theRX1 located within the power transmission/reception range, the TX1should not perform transmission of a power to charge the battery of theRX1, a negotiation concerning the power, and the like. If the TX1 setsthe RX1 as the power transmission target but establishes BLE connectionwith the RX2 or the second communication apparatus 122 and performscontrol communication, the power transmission target (RX1) and thepartner apparatus (the RX2 or the second communication apparatus 122) ofthe control communication may be different. In this case, the TX1 cannotperform appropriate control communication for the RX1. Similarly, whenusing control communication by the BLE (out-band communication), ifthere is no proof for BLE connection with the TX1 located within thepower transmission/reception range, the RX1 should not perform receptionof a power from the TX1 to charge the battery, a negotiation concerningthe power, and the like. If the RX1 sets the TX1 as the power receptionsource but establishes BLE connection with the TX2 or the firstcommunication apparatus 121 and performs control communication, thepower reception source (TX1) and the partner apparatus (the TX2 or thefirst communication apparatus 121) of the control communication may bedifferent. In this case, the RX1 cannot perform appropriate controlcommunication with the TX1.

As described above, in the wireless power transmission system shown inFIG. 1, it is important that both the power transmission apparatus andthe power receiving apparatus obtain a proof that they can performcontrol communication by the BLE with the partner apparatus locatedwithin the power transmission/reception range beforetransmission/reception of a power to charge the battery or a negotiationconcerning the power. Hence, this embodiment enables each of the powertransmission apparatus and the power receiving apparatus to establishconnection by the BLE with the partner apparatus of wireless powertransmission. Note that the BLE is merely an example, and an arbitrarywireless communication method usable for out-band communication inwireless power transmission can be used. In addition, the wireless powertransmission to be executed is assumed to comply with the WPC standard,and the WPC standard here includes a function defined by version 1.2.2.Note that in this embodiment, a description will be made assuming thatthe power transmission apparatus and the power receiving apparatuscomply with the WPC standard. However, the present disclosure is notlimited to this, and the standard may be another wireless powertransmission standard. An example of the arrangement of each of thepower transmission apparatus and the power receiving apparatus and anexample of the procedure of processing to be executed will be describedbelow.

(Apparatus Arrangement)

FIG. 2 is a block diagram showing an example of the arrangement of thepower transmission apparatus (for example, the TX1 and the TX2). Thepower transmission apparatus includes, for example, a control unit 201,a power supply unit 202, a power transmission unit 203, a firstcommunication unit 204, a power transmission coil 205, a secondcommunication unit 206, and a memory 207.

The control unit 201 controls the entire power transmission apparatus.As one example, the control unit 201 includes at least one processorsuch as a CPU (Central Processing Unit) or an MPU (Micro ProcessingUnit). Note that the control unit 201 may include an ASIC (ApplicationSpecific Integrated Circuit), an FPGA (Field Programmable Gate Array),or the like configured to execute processing to be described later.

The power supply unit 202 is a power supply that supplies a power whenat least the control unit 201 and the power transmission unit 203operate. The power supply unit 202 can be, for example, a wired powerreceiving circuit, a battery, or the like configured to receive supplyof a power from a commercial power supply. The power transmission unit203 causes the power transmission coil 205 to generate an alternatingvoltage and an alternating current to transmit a power to the powerreceiving apparatus via the power transmission coil 205. The powertransmission unit 203 converts, for example, a direct voltage suppliedfrom the power supply unit 202 into an alternating voltage using aswitching circuit having a half-bridge or full-bridge structure using anFET. In this case, the power transmission unit 203 includes a gatedriver configured to on/off-control the FET.

The first communication unit 204 performs control communication forwireless power transmission based on the WPC standard with acommunication unit (a first communication unit 303 shown in FIG. 3) ofthe power receiving apparatus. In this embodiment, the communicationexecuted by the first communication unit 204 is so-called in-bandcommunication (communication by a first method) that modulates thealternating voltage or current generated by the power transmission unit203 and superimposes communication target data on wireless power.Additionally, in this embodiment, when using only in-band communicationfor control communication, the power transmission apparatus can supply apower to output a power of 15 W at maximum to the charge unit of thepower receiving apparatus that similarly uses in-band communication.

The second communication unit 206 performs control communication forwireless power transmission based on the WPC standard with acommunication unit (a second communication unit 304 shown in FIG. 3) ofthe power receiving apparatus. The second communication unit 206performs so-called out-band communication (communication by a secondmethod) in which a frequency different from the frequency of the powertransmission unit 203 is used, and an antenna (not shown) different fromthe power transmission coil 205 is used. In this embodiment, the secondcommunication unit 206 is compliant with the BLE. Instead, acommunication unit compliant with another wireless communication methodsuch as NFC or WiFi may be used.

Note that in this embodiment, when out-band communication is used forcontrol communication with the power receiving apparatus, the powertransmission apparatus can supply a larger power to the power receivingapparatus as compared to a case in which in-band communication is used.For example, when performing control communication by out-bandcommunication, the power transmission apparatus can supply a power suchthat the power output to the charge unit of the power receivingapparatus becomes 100 W at maximum. In in-band communication, smallvoltage and current changes are superimposed on transmission power forcommunication. On the other hand, when the transmission power becomeslarge, noise generated from the power transmission unit or the powerreceiving unit becomes large. For this reason, when in-bandcommunication is used, the transmission power is limited such that thecommunication unit of in-band communication can detect the small voltageand current changes for communication. On the other hand, when usingout-band communication, the amount of the power to be transmitted can bemade large because such a limitation is absent.

The memory 207 stores the states of the whole and the elements of thepower transmission apparatus and the wireless power transmission system.

In FIG. 2, the control unit 201, the power supply unit 202, the powertransmission unit 203, the first communication unit 204, the memory 207,and the second communication unit 206 are illustrated as separateblocks. However, two or more of the blocks may be integrated by one chipor the like. Also, one block may be divided into a plurality of blocks.

FIG. 3 is a block diagram showing an example of the arrangement of thepower receiving apparatus (for example, the RX1 and the RTX2). The powerreceiving apparatus includes, for example, a control unit 301, a powerreceiving unit 302, the first communication unit 303, the secondcommunication unit 304, a power receiving coil 305, a charge unit 306, abattery 307, and a memory 308.

The control unit 301 controls the entire power receiving apparatus. Asone example, the control unit 301 includes at least one processor suchas a CPU (Central Processing Unit) or an MPU (Micro Processing Unit).Note that the control unit 301 may include an ASIC (Application SpecificIntegrated Circuit), an FPGA (Field Programmable Gate Array), or thelike configured to execute processing to be described later.

The power receiving unit 302 obtains an alternating voltage and analternating current generated in the power receiving coil 305 by aposition transmitted from the power transmission coil 205, and convertsthe received power into a direct voltage and a direct current to operatethe control unit 301, the charge unit 306, and the like. The firstcommunication unit 303 performs control communication for wireless powertransmission based on the WPC standard with the first communication unit204 of the power transmission apparatus. The control communication isperformed by in-band communication (communication by the first method)that performs load modulation of an electromagnetic wave received by thepower receiving coil 305. In this embodiment, when using only in-bandcommunication for control communication with the power transmissionapparatus, the power receiving apparatus can wirelessly receive a powerfrom the power transmission apparatus, and output a power of 15 W atmaximum to the charge unit 306.

The second communication unit 304 performs control communication forwireless power transmission based on the WPC standard with the secondcommunication unit 206 of the power transmission apparatus. The secondcommunication unit 304 performs out-band communication (communication bythe second method) using a frequency different from the frequency of theelectromagnetic wave received by the power receiving unit 302 and anantenna (not shown) different from the power receiving coil 305. In thisembodiment, the second communication unit 304 is compliant with the BLE.Instead, a communication unit compliant with another wirelesscommunication method such as NFC or WiFi may be used. In addition, thesecond communication unit 304 may receive power supply from the battery307, or may directly receive power supply from the power receiving unit302 without an intervention of the battery 307. Note that in thisembodiment, when out-band communication is used for controlcommunication with the power transmission apparatus, the power receivingapparatus can wirelessly receive a power from the power transmissionapparatus and output a power of 100 W at maximum to the charge unit 306.

The charge unit 306 charges the battery 307 using the direct voltage andthe direct current supplied from the power receiving unit 302. Thememory 308 stores the states of the whole and the elements of the powerreceiving apparatus and the wireless power transmission system.

In FIG. 3, the control unit 301, the power receiving unit 302, the firstcommunication unit 303, the second communication unit 304, the chargeunit 306, and the memory 308 are illustrated as separate blocks.However, two or more of the blocks may be integrated by one chip or thelike. Also, one block may be divided into a plurality of blocks.

Note that “the power transmission apparatus or power receiving apparatusis compliant with control communication by out-band communication” willbe expressed as “compliant with a version A of the WPC standard”hereinafter. The version A of the WPC standard is a standard thatreplaces WPC v1.2.2, and at least a control communication function byout-band communication is added.

(Procedure of Processing)

An example of the procedure of processing executed by each apparatuswill be described next, and an example of the procedure of processing ofthe entire system will be described after that.

[Operation of Power Transmission Apparatus]

An example of the procedure of processing executed by the powertransmission apparatus (TX1) will be described below with reference toFIGS. 4A and 4B. Note that this processing can be started when the powertransmission unit 203 receives power supply from the power supply unit202, and the power transmission apparatus is thus activated. Inaddition, this processing can be implemented when the control unit 201executes a program stored in the memory 207. However, the presentdisclosure is not limited to this, and this processing may be executedwhen the power transmission function is activated by, for example, auser operation such as pressing of a predetermined button. In addition,at least part of the processing shown in FIGS. 4A and 4B may beimplemented by hardware. When at least part of the processing isimplemented by hardware, for example, a dedicated circuit automaticallygenerated on an FPGA using a predetermined compiler from a programconfigured to implement the processing steps can be used. Alternatively,hardware configured to execute a predetermined processing step may beimplemented by a Gate Array circuit, like the FPGA.

When this processing is started, the TX1 starts processing complyingwith the WPC standard. In the WPC standard, a partner apparatus isspecified by a selection phase, a ping phase, and an identification &configuration phase (to be referred to as an “I & C phase” hereinafter).Then, in a negotiation phase, a negotiation concerning a transmissionpower is executed. After that, a calibration phase for powertransmission is executed, and then, processing of a power transfer phase(to be referred to as a “PT phase” hereinafter) for performing actualpower transmission is executed.

Referring to FIGS. 4A and 4B, the TX1 first executes the processing ofthe selection phase and the ping phase (step S401). In the selectionphase, the TX1 transmits Analog Ping via the power transmission coil205. The Analog Ping is a small power used to detect an object existingnear the power transmission coil 205. The TX1 detects the voltage valueor current value of the power transmission coil at the time oftransmission of the Analog Ping. If the voltage is less than athreshold, or if the current value exceeds a threshold, it is determinedthat an object exists in the neighborhood, and the phase transitions tothe ping phase. In the ping phase, the TX1 transmits a Digital Pingwhose power is larger than the Analog Ping. Here, the Digital Ping has apower enough to activate the control unit 301, the first communicationunit 303, and the second communication unit 304 of the RX1 existing nearthe power transmission coil 205. When the control unit 301 and the firstcommunication unit 303 of the RX1 are activated by the Digital Pingreceived via the power receiving coil 305, the RX1 notifies the TX1 ofthe magnitude of the received voltage by in-band communication by thefirst communication unit 303. Upon receiving the notification of thereceived voltage value via the first communication unit 204, the TX1ends the processing of the ping phase and transitions to the I & Cphase. In the I & C phase, the TX1 receives an Identification Packettransmitted by the RX1 (step S402). At this time, the TX1 can obtaininformation representing whether the RX1 that is the transmission sourceof the packet is compliant with the version A of the WPC standard, theindividual identification information of the RX1 used at least in theWPC standard of a version before the version A, and identificationinformation used in the BLE. In one example, the TX1 obtains, in theIdentification Packet, identification information used by the RX1 in theWPC standard, and confirms whether an EXT bit representing thatadditional ID information exists is “1”. If the EXT bit is “1”, the TX1obtains the additional ID information by an Extended IdentificationPacket transmitted next in accordance with the WPC standard. In thisembodiment, the Extended Identification Packet stores an 8-byteBluetooth Device Address used by the RX1 in the BLE. Note that theBluetooth Device Address will be referred to as “BD_ADDR” hereinafter.The BD_ADDR is a Public Address defined by the BLE standard andrepresenting, for example, the manufacturer of the RX1 of the individualidentification information of the communication function (secondcommunication unit 304) in the BLE. At this point of time, the TX1 canrecognize that the identification information of the RX1, which is usedin the WPC standard, corresponds to the identification information inthe BLE (the pieces of identification information concern the sameapparatus).

Additionally, in the I & C phase, the TX1 also receives a ConfigurationPacket transmitted by the RX1 (step S402). In this embodiment, a BLE bitrepresenting whether the RX1 that is the transmission source of thepacket is compliant with control communication by the BLE is transmittedusing one bit in the Configuration Packet. The TX1 compliant with theversion A of the WPC standard monitors this bit, thereby determiningwhether the RX1 has the control communication function using the BLE.Additionally, in this embodiment, a BLE Enable bit representing whetherthe RX1 can use BLE for control communication at that point of time istransmitted using another bit in the Configuration Packet. TheConfiguration Packet has a structure as shown in FIG. 7, and the BLEbit/BLE Enable bit can be set in one of Reserved fields (fields 700,701, and 702). At this time, if the RX1 is compliant with controlcommunication of the BLE, the field (bit) in which the BLE bit is set isset to “1”. If BLE can be used for control communication, the field inwhich the BLE Enable bit is set is set to “1”. Since “0” is normallystored in the Reserved field, a power receiving apparatus compliant witha version before the version A of the WPC standard stores “0” in thisfield. This can prevent the power transmission apparatus frommisunderstanding that the power receiving apparatus that does not complywith the version A of the WPC standard is compliant with controlcommunication by the BLE or can execute control communication. Note thatthis is merely an example, and the Configuration Packet need not alwaysinclude these elements. For example, when the BD_ADDR is transmitted bythe Extended Identification Packet in the above-described way, it can beknown that the RX1 is compliant with communication by the BLE, andtherefore, the BLE bit may be omitted. In this case, when, for example,the RX1 is not performing communication by the BLE with any otherapparatus, the RX1 can transmit only the BLE Enable bit to allow the TX1to grasp whether the RX1 can execute control communication by the BLE.Note that the BLE bit and the BLE Enable bit are merely examples, andthese may not be used. For example, whether the RX1 is compliant without-band communication that is not limited to the BLE and whether theRX1 is in a state in which it is possible to execute controlcommunication by out-band communication when transmitting theConfiguration Packet may be shown. Alternatively, the same field as theBLE bit or BLE Enable bit, which represents, for each of thecommunication methods usable for out-band communication other than BLE,whether the RX1 has the communication function or whether it can executecontrol communication may be provided. For example, an NFC bitrepresenting whether the RX1 has an NFC communication function may beprovided.

In response to the Configuration Packet, the TX1 transmits anacknowledgement (ACK) by in-band communication (step S403). According tothe transmission of the ACK, the TX1 transitions to the negotiationphase.

In addition, the TX1 determines, by receiving the Configuration Packet,whether the RX1 has the control communication function by the BLE and isin a state in which it is possible to perform control communication bythe BLE with the TX1 (step S404). In a case in which the RX1 does nothave the control communication function by the BLE, or the RX1 is not inthe state in which it is possible to perform control communication bythe BLE (NO in step S404), the TX1 determines not to use out-bandcommunication because the control communication by the BLE cannot beperformed with the RX1 (step S420). In this case, the TX1 executesin-band communication in place of out-band communication. Then, the TX1determines to set the maximum allowable value of a Guaranteed Power (GP)to 15 W (step S421). Note that the GP indicates a power value guaranteedby the power transmission apparatus concerning the power output from thepower receiving unit 302 to the load (for example, the charge unit orthe battery) even if the position relationship between the powertransmission apparatus and the power receiving apparatus is shifted, andthe power transmission efficiency between the power transmission coil205 and the power receiving coil 305 lowers. The TX1 determines themagnitude of the allowable GP, and in a case in which a GP more than theallowable value is requested by the subsequent negotiation, operates toreject the request. After that, the TX1 advances the process to stepS414.

On the other hand, in a case in which the RX1 has the controlcommunication function by the BLE and is in the state in which it ispossible to perform control communication by the BLE (YES in step S404),the TX1 determines whether an inquiry about capability information isreceived from the RX1 (step S405). The inquiry about capabilityinformation is done by transmitting a General Request that is datadefined by the WPC standard from the RX1 to the TX1. Note that theGeneral Request configured to inquire about capability information willbe referred to as a “General Req (Capability)” hereinafter. If theGeneral Req (Capability) is not received (NO in step S405), the TX1advances the process to step S420 to determine not to use out-bandcommunication. On the other hand, if the General Req (Capability) isreceived (YES in step S405), the TX1 transmits a Power TransmitterCapability Packet defined by the WPC standard to the RX1. The PowerTransmitter Capability Packet will be referred to as a “TX CapabilityPacket” hereinafter. As shown in FIG. 8, the TX Capability Packetincludes information concerning the capability of the power transmissionapparatus such as the maximum value of the GP. In this embodiment, onebit of the reserved fields (fields 800 and 801 in FIG. 8) of the TXCapability Packet is assigned as a BLE Enable bit. The BLE Enable bithas the same meaning as the BLE Enable bit in the Configuration Packettransmitted by the RX1. Note that the TX1 may use one bit of thereserved fields of the TX Capability Packet as a BLE bit. The BLE bitalso has the same meaning as the BLE bit in the Configuration Packettransmitted by the RX1.

Before the information transmission by the TX Capability Packet, the TX1determines whether the self-apparatus is in a state in which it ispossible to use the BLE (step S406). If the self-apparatus is not in thestate in which it is possible to use the BLE (NO in step S406), the TX1sets the BLE Enable bit of the TX Capability Packet to “0” and transmitsit to the RX1 (step S419), and advances the process to step S420. On theother hand, the TX1 determines, based on, for example, whether theself-apparatus is operating as a Peripheral of the BLE or using the BLEwith another apparatus, whether control communication by the BLE can beexecuted at the current time. For example, if the self-apparatus is aCentral, the TX1 can be connected to a plurality of Peripherals. Hence,the TX1 can determine that the BLE can be used for controlcommunication. Additionally, if the self-apparatus is not performingcommunication by the BLE with another apparatus, the TX1 can determinethat the BLE can be used for control communication. On the other hand,if the self-apparatus is serving as a Peripheral and performingcommunication by the BLE with another apparatus, the TX1 can determinethat the BLE cannot be used for control communication. Additionally, theTX1 may perform this determination by communication with the controlunit of a product (for example, a printer) connected to the TX1. Forexample, the control unit 201 of the TX1 and the control unit of theproduct may be connected by GPIO (General Purpose Input/Output) orserial communication, and the control unit 201 of the TX1 may inquire ofthe control unit of the product about the use state of the BLE. In thiscase, if the response concerning the use state of the BLE from thecontrol unit of the product represents that the BLE is being used, thecontrol unit 201 of the TX1 can determine that the BLE cannot be usedfor control communication at this point of time. In addition, if theresponse represents that the BLE is not being used, the control unit 201of the TX1 can determine that the BLE can be used for controlcommunication.

In a case in which the self-apparatus can use the BLE (YES in stepS406), the TX1 sets the BLE Enable bit of the TX Capability Packet to“1” and transmits it to the RX1 (step S407). The TX1 determines thatcommunication by the BLE can be performed with the RX1 at this point oftime, and holds the BD_ADDR of the RX1 obtained in step S402 in thememory (step S408). Note that the TX1 may hold the BD_ADDR of the RX1 inthe memory when it is obtained in step S402, and may discard theinformation upon determining that the self-apparatus cannot use the BLE(NO in step S406).

Note that after the TX Capability Packet with the BLE Enable bit set to“1” is transmitted in step S407, the TX1 may receive, from the RX1, asignal for inquiring about the identification information of the BLE ofthe TX1. This signal can be, for example, a General Request of the WPCstandard. The General Request for inquiring about the identificationinformation of the BLE will be referred to as a “General Req (ID)”hereinafter. Upon receiving the General Req (ID), the TX1 transmits aresponse including a BD_ADDR concerning the BLE of the self-apparatus tothe RX1. This response can be a Power Transmitter Identification Packet(to the referred to as a “TX ID Packet” hereinafter) defined by the WPCstandard. The TX ID Packet includes the version of the WPC standard withwhich the power transmission apparatus is compliant and anidentification number by the manufacturer or the like of a functionalblock of the power transmission apparatus concerning in-bandcommunication. In addition, the power transmission apparatus compliantwith the version A can include the BD_ADDR of the BLE in the TX IDPacket. This allows the RX1 to recognize the identification informationof the TX1 in the WPC standard and the identification information(BD_ADDR) in the BLE in association with each other.

Next to the process of step S408, to attempt control communication bythe BLE with the RX1, the TX1 activates the BLE communication functionof the self-apparatus as a scanner (step S409). Note that the scanner isone of the states defined by the BLE standard. The scanner receives abroadcast ADVERTISE_INDICATION and finds a BLE device (or service) asthe transmission source. The ADVERTISE_INDICATION will be referred to asan ADV_IND hereinafter. The ADV_IND is a signal that is broadcast by adevice in a state of advertiser defined by the BLE standard andadvertises the BD_ADDR of the device or compliant service information.

After activated as the scanner, the TX1 waits for transmission of theADV_IND (step S410). Upon receiving the ADV_IND of the BD_ADDR held instep S408 before the elapse of a predetermined time (during NO in stepS418) (YES in steps S410 and S411), the TX1 transmits a connectionrequest message by the BLE to the BD_ADDR (step S412). That is, when theADV_IND from the RX1 is received before timeout, the TX1 transmits theconnection request message by the BLE to the RX1. The connection requestmessage is a CONNECT_REQ (to be sometimes referred to as a “CONNECT”hereinafter) defined by the BLE standard. Then, the TX1 transitions tothe negotiation phase. Here, since communication by the BLE is possible,the negotiation in the negotiation phase is executed using the BLE.Since the state in which it is possible to execute control communicationby the BLE (out-band communication) is obtained at this point of time,the TX1 determines that the GP can be set sufficiently high. For thisreason, the TX1 sets the allowable maximum value of the GP to, forexample, 100 W (step S413) and advances the process to step S414. Notethat the TX1 may execute the processing of determining the maximum valueof the allowable value of the GP after connection in out-bandcommunication is actually established. In this case, if it is determinedto use the out-band communication, but connection in the out-bandcommunication cannot actually be established, the TX1 may advance theprocess to step S420.

Note that if an ADV_IND is received, but it is not the ADV_IND of theBD_ADDR held in step S408 (NO in step S411), the TX1 1 does not transmitthe CONNECT. That is, at the stage of attempting control communicationfor power transmission, the TX1 1 limits the target of CONNECTtransmission so the connection of the BLE is not established for anapplication purpose different from such control communication. Note thatif timeout occurs before the ADV_IND from the RX1 is received (YES instep S418), the process advances to step S420.

In step S414, the TX1 performs a negotiation concerning the GP with theRX1. This negotiation is performed based on the maximum value of the GPallowable in the TX1 and the value of the GP requested by the RX1. Notethat the maximum value of the GP allowable in the TX1 is determined bythe process of step S413 or S421 depending on whether out-bandcommunication is usable, as described above. After that, the TX1executes processing in the calibration phase (step S415) and thentransitions to the PT phase (step S416) to transmit the power to theRX1. In the PT phase, control data to request to increase/decrease thetransmission power is transmitted from the RX1 to the TX1. Thiscommunication is control communication and is therefore performed by theBLE in a state in which it is possible to use the BLE (out-bandcommunication). After that, upon receiving an End Power Transfer (EPT)to request stop of power transmission from the RX1 based on the end ofcharge or the like (step S417), the TX1 ends the power transmissionprocessing. Note that the transmission/reception of the EPT is alsocontrol communication and is therefore performed by the BLE in a statein which it is possible to use the BLE (out-band communication).

As described above, the TX1 confirms whether the RX1 can execute controlcommunication by the BLE. In addition, the TX1 recognizes theidentification information of the RX1 in the WPC standard and theidentification information in the BLE in association with each other,and transmits the CONNECT upon receiving an ADV_IND including theidentification information of the RX1 in the BLE. This makes it possibleto establish connection by the BLE with the target of power transmissionand inhibit establishment of connection by the BLE with anotherapparatus that is not the target of power transmission.

[Operation of Power Receiving Apparatus]

An example of the procedure of processing executed by the powerreceiving apparatus (RX1) will be described next with reference to FIGS.5A and 5B. Note that this processing can be executed when the powerreceiving function is activated by, for example, a user operation suchas pressing of a predetermined button, or when the RX1 is brought to theneighborhood of the TX1. Note that this processing may be started whenthe control unit 301 and the first communication unit 303 are activatedby a power received via the power receiving coil 305. In addition, thisprocessing can be implemented when the control unit 301 executes aprogram stored in the memory 308. However, dedicated hardware configuredto execute processing to be described later may be used. For example,when at least part of the processing is implemented by hardware, adedicated circuit automatically generated on an FPGA using apredetermined compiler from a program configured to implement theprocessing steps can be used. Alternatively, hardware configured toexecute a predetermined processing step may be implemented by a GateArray circuit, like the FPGA.

Referring to FIGS. 5A and 5B, the RX1 is first placed near the TX1 andthus detected by the TX1. Accordingly, the TX1 transmits a Digital Ping.The control unit 301 and the first communication unit 303 of the RX1 areactivated by the Digital Ping received via the power receiving coil 305and measure the magnitude of the received voltage of the Digital Ping.The RX1 then notifies the TX1 of the magnitude of the received voltageby in-band communication (step S501). After that, the RX1 transitions tothe I & C phase.

In the I & C phase, the RX1 transmits an Identification Packet to theTX1 by in-band communication (step S502). At this time, theIdentification Packet includes information representing whether the RX1is compliant with the version A of the WPC standard and the individualidentification information used at least in the WPC standard of aversion before the version A. Note that the individual identificationinformation used in the WPC standard is identification information usedin a case in which control communication is performed by in-bandcommunication. In addition, the RX1 can set, in the IdentificationPacket, an EXT bit representing that additional ID information existsand transmit it. If additional ID information exists, the RX1 sets theEXT bit of the Identification Packet to “1”, and transmits an ExtendedIdentification Packet to transmit the additional ID information. TheExtended Identification Packet is also transmitted by in-bandcommunication according to the WPC standard. In this embodiment, an8-byte BD_ADDR used in the BLE is transmitted by the ExtendedIdentification Packet.

After transmission of the Identification Packet, the RX1 transmits theConfiguration Packet. At this time, first, the RX1 determines whetherthe self-apparatus is in a state in which it is possible to use the BLEfor control communication (step S503). Whether the BLE can be used forcontrol communication is determined based on, for example, whether theself-apparatus is operating as a Peripheral of the BLE or using the BLEwith another apparatus. For example, if the self-apparatus is a Central,the RX1 can be connected to a plurality of Peripherals. Hence, the RX1can determine that the BLE can be used for control communication.Additionally, if the self-apparatus is not performing communication bythe BLE with another apparatus, the RX1 can determine that the BLE canbe used for control communication. On the other hand, if theself-apparatus is serving as a Peripheral and performing communicationby the BLE with another apparatus, the RX1 can determine that the BLEcannot be used for control communication. Additionally, the RX1 mayperform this determination by communication with the control unit of aproduct (for example, a smartphone or a camera) connected to the RX1.For example, the control unit 301 of the RX1 and the control unit of theproduct may be connected by GPIO (General Purpose Input/Output) orserial communication, and the control unit 301 of the RX1 may inquire ofthe control unit of the product about the use state of the BLE. In thiscase, if the response concerning the use state of the BLE from thecontrol unit of the product represents that the BLE is being used, thecontrol unit 301 of the RX1 can determine that the BLE cannot be usedfor control communication at this point of time. In addition, if theresponse represents that the BLE is not being used, the control unit 301of the RX1 can determine that the BLE can be used for controlcommunication. Note that the information representing whether the RX1 iscompliant with communication by the BLE and whether the BLE can be usedfor control communication can be transmitted using the Reserved field ofthe Configuration Packet, as described above.

In a case in which the self-apparatus cannot use the BLE for controlcommunication at the current time (NO in step S503), the RX1 transmitsthe Configuration Packet with the BLE Enable bit set to “0” to the TX1by in-band communication (step S520). Since it is impossible to performcontrol communication using the BLE with the TX1, the RX1 determines notto use out-band communication (step S521). In this case, the RX1executes in-band communication in place of out-band communication. Then,the RX1 determines to set the maximum value of the GP to be requested to15 W (step S522), and advances the process to step S523.

On the other hand, in a case in which the self-apparatus can use the BLEfor control communication at the current time (YES in step S503), theRX1 transmits the Configuration Packet with the BLE Enable bit set to“1” to the TX1 by in-band communication (step S504). After that, the RX1waits for an ACK from the TX1 (step S505). If the ACK is not received(NO in step S505), the RX1 transitions to the PT phase (step S525) toreceive a power transmitted from the TX1. Then, the RX1 transmits an EPTto the TX1 in accordance with determining to end the power transmissionbased on the completion of charge of the battery 307 (step S526), andends the processing. A power transmission apparatus that is compliantwith only a version before the version 1.2 of the WPC standard is notcompliant with the negotiation phase and the calibration phase. For thisreason, upon receiving the Configuration Packet, the power transmissionapparatus transitions to the PT phase without transmitting the ACK.Hence, the RX1 transitions to the PT phase in a case in which the ACK isnot received from the TX1, thereby performing power reception even in acase in which the TX1 is a power transmission apparatus of a versionbefore the version 1.2 of the WPC standard. That is, with thisarrangement, the RX1 can ensure backward compatibility. Note that if theACK is not received, the maximum value of the power that can be suppliedby the power receiving unit 302 to the load (the charge unit 306 and thebattery 307) is limited to 5 W.

Upon receiving the ACK (YES in step S505), the RX1 transmits a GeneralReq (Capability) that inquires about the capability information of theTX1 (step S506) and waits for the response (TX Capability Packet) (stepS507). If the TX Capability Packet is not received (NO in step S507),the RX1 determines not to use out-band communication (step S521), andexecutes processing from step S522 described above. Upon receiving theTX Capability Packet (YES in step S507), the RX1 confirms the BLE bitand the BLE Enable bit of the packet and determines whether the TX1 canexecute control communication by the BLE (step S508). Upon determiningthat the TX1 cannot execute control communication by the BLE (NO in stepS508), the process advances to step S521.

Upon determining that the TX1 can execute control communication by theBLE (YES in step S508), the RX1 transmits a General Req (ID) to obtainthe identification information of the TX1 in the BLE (step S509). TheRX1 waits for a TX ID Packet from the TX1 as a response to the GeneralReq (ID) (step S510). If the TX ID Packet is not received from the TX1(NO in step S510), the RX1 determines not to use out-band communication(step S521), and executes processing from step S522 described above. Onthe other hand, upon receiving the TX ID Packet from the TX1 compliantwith the version A of the WPC standard (YES in step S510), the RX1obtains the BD_ADDR of the TX1, which is stored in the packet, and holdsit in the memory 308 (step S511). At this point of time, the RX1 canrecognize the identification information of the TX1 in the WPC standardand the BD_ADDR in the BLE in association with each other. Then, toperform control communication by the BLE with the TX1, the RX1 activatesthe self-apparatus as an advertiser of the BLE (step S512) andbroadcasts an ADV_IND (step S513). Note that the advertiser is one ofthe states defined by the BLE standard. The advertiser has a role ofadvertising the BD_ADDR of the self-apparatus or compliant serviceinformation by the ADV_IND such that the above-described scanner canfind a BLE device (or service). Here, the ADV_IND includes a UUID(Universally Unique IDentifier) representing a service (provider) withwhich the second communication unit 304 is compliant. Note that in thisembodiment, a UUID representing a wireless charge service (to bereferred to as a “wireless charge service” hereinafter) using out-bandcommunication according to the WPC standard is included in the ADV_IND.In addition, the ADV_IND can also include pieces of information such asthe device type (for example, a camera or a smartphone), the maker name,the model name, and the serial number of the product to which the powerreceiving apparatus (RX1) is connected.

After that, the RX1 waits for a CONNECT transmitted from the scannerthat has received the ADV_IND (step S514). Upon receiving the CONNECT(YES in step S514), the RX1 determines whether the identificationinformation of the transmission source of the CONNECT is held in thememory 308 as the identification information (BD_ADDR) of the TX1 (stepS515). That is, the RX1 determines whether the transmission source ofthe CONNECT is the TX1. Here, if the transmission source of the CONNECTis not the TX1 (NO in step S515), the RX1 transmits an LL_TERMINATE_INDrepresenting disconnection of the BLE connection established by theCONNECT to the apparatus of the transmission source of the CONNECT (stepS518). Note that the LL_TERMINATE_IND will be referred to as a“TERMINATE” hereinafter. If the CONNECT from the TX1 is not received (NOin step S514 or S515), the RX1 repetitively transmits the ADV_IND untila predetermined time elapses from the start of transmission of theADV_IND, and timeout occurs (during NO in step S519) (step S513). Iftimeout occurs without receiving the CONNECT from the TX1 (YES in stepS519), the RX1 determines not to use out-band communication (step S521),and executes processing from step S522 described above.

On the other hand, upon receiving the CONNECT from the TX1 (YES in stepsS514 and S515), the RX1 determines to use out-band communication (stepS516), and determines to set the maximum value of the GP to be requestedto 100 W (step S517). Note that the RX1 may perform the determinationprocessing of the requested value of the GP in accordance with thedetermining to use out-band communication, or may execute the processingafter connection in out-band communication is actually established. Inaddition, if it is determined to use the out-band communication in stepS516, but connection in the out-band communication cannot actually beestablished, the RX1 may advance the process to step S521. After that,the RX1 advances the process to step S523. In step S523, the RX1performs a negotiation concerning the GP with the TX1. This negotiationis performed based on the maximum value of the GP allowable in the TX1and the value of the GP requested by the RX1. Note that the maximumvalue of the GP requested by the RX1 is determined by the process ofstep S517 or S522 depending on whether out-band communication is usable,as described above. After that, the RX1 executes processing in thecalibration phase (step S524) and then transitions to the PT phase (stepS525) to receive a power from the TX1. In the PT phase, control data torequest to increase/decrease the transmission power is transmitted fromthe RX1 to the TX1. This communication is control communication and istherefore performed by the BLE in a state in which it is possible to usethe BLE (out-band communication). After that, in accordance with, forexample, the end of charge, the RX1 transmits an EPT representing arequest of stop of power transmission for battery charge to the TX1 bythe BLE (out-band communication) (step S526). Then, the RX1 transmitsthe TERMINATE to disconnect the connection of the BLE as needed and endsthe processing. Note that the transmission of the TERMINATE after thetransmission of the EPT may be done by the TX1.

As described above, the RX1 confirms whether the TX1 can execute controlcommunication by the BLE. In addition, the RX1 recognizes theidentification information of the TX1 in the WPC standard and theidentification information in the BLE in association with each other,and upon receiving the CONNECT that does not include the identificationinformation of the TX1 in the BLE, disconnects the connection andreceives only the CONNECT from the TX1. This makes it possible toestablish connection by the BLE with the target of power transmissionand inhibit establishment of connection by the BLE with anotherapparatus that is not the target of power transmission.

[Procedure of Processing of Power Transmission System]

An example of the procedure of processing executed by the powertransmission system will be described next with reference to FIG. 6.First, when the power transmission unit 203 of the TX1 receives powersupply from the power supply unit 202 and is thus activated, the TX1starts an operation complying with the WPC standard. That is, first, inthe selection phase, the TX1 transmits the Analog Ping via the powertransmission coil 205 (step M601). The TX1 detects the existence of theRX1 near the self-apparatus (within the power transmission/receptionrange), as shown in FIG. 3, by the Analog Ping, and transitions to theping phase. In the ping phase, the TX1 transmits the Digital Ping (stepM602). When the control unit 301 and the first communication unit 303 ofthe RX1 are activated by the Digital Ping received via the powerreceiving coil 305, the RX1 notifies the TX1 of the magnitude of thereceived voltage by in-band communication by the first communicationunit 303 (step M603), and transitions to the I & C phase. Upon receivingthe notification of the received voltage value, the TX1 ends theprocessing in the ping phase and transitions to the I & C phase.

Next, the RX1 transmits the Identification Packet to the TX1 using thefirst communication unit 303 (step M604). Here, by the IdentificationPacket, the RX1 notifies the TX1 of information representing that theRX1 is compliant with the version A of the WPC standard and theindividual identification information of the RX1 used at least in theWPC standard of a version before the version A. Additionally, in thisprocessing example, to transmit the identification information used inthe BLE later, the RX1 sets the EXT bit to “1” and transmits theIdentification Packet. Then, the RX1 includes the 8-byte BD_ADDR used inthe BLE in the Extended ID Packet and transmits it by in-bandcommunication (step M605). In this processing example, the RX1 transmitsthe Configuration Packet in which the BLE bit representing that theself-apparatus is compliant with control communication by the BLE is setto “1” (step M606). Additionally, in the Configuration Packet, the BLEEnable bit is set to “1”.

The TX1 transmits an acknowledgement (ACK) by in-band communication tothe Configuration Packet from the RX1 (step M607). After thetransmission of the ACK, the TX1 transitions to the negotiation phase.In addition, upon receiving the ACK, the RX1 ends the I & C phase andtransitions to the negotiation phase. Note that at this point of time,the TX1 can recognize the identification information of the RX1 in theWPC standard and the BD_ADDR in the BLE in association with each other.The TX1 can also recognize that the RX1 is compliant with controlcommunication by the BLE.

After that, to obtain information about the capability of the TX1, theRX1 transmits the General Req (Capability) by in-band communication(step M608). Upon receiving the General Req (Capability), the TX1transmits the TX Capability Packet to the RX1 (step M609). Here, the TX1transmits the TX Capability Packet whose BLE bit/BLE Enable bit is setto “1” so as to include information representing that the self-apparatusis compliant with the version A of the WPC standard and can executecontrol communication by the BLE. At this time, upon receiving the TXCapability Packet, the RX1 can recognize that the TX1 is compliant withcontrol communication by the BLE and can use the BLE for controlcommunication. Next, the RX1 transmits the General Req (ID) by in-bandcommunication to request transmission of the identification informationof the TX1 (step M610). Upon receiving the General Req (ID), the TX1transmits the TX ID Packet to the RX1 by in-band communication (stepM611). At this point of time, the RX1 can recognize the identificationinformation of the TX1 in the WPC standard and the BD_ADDR in the BLE inassociation with each other. The RX1 can also recognize that the TX1 iscompliant with control communication by the BLE.

After that, to attempt control communication by the BLE with the TX1,the RX1 activates the BLE of its own as the advertiser and transmits theADV_IND (step M612). Note that at this time, the TX1 holds, in thememory, the BD_ADDR of the RX1 obtained in step M605, and activates theself-apparatus as the scanner of the BLE to perform controlcommunication by the BLE with the RX1.

Here, assume that not only the TX1 but also another apparatus (forexample, the first communication apparatus 121) operates as a scanner.At this time, the other apparatus is assumed to receive the ADV_INDtransmitted from the RX1 in step M612 and transmit a CONNECT to the RX1to request connection by the BLE (step M613). Upon receiving theCONNECT, the RX1 refers to the memory 308 and determines whether theidentification information of the transmission source of the CONNECTmatches the identification information (BD_ADDR) of the TX1. In thiscase, since the other apparatus is different for the TX1, the RX1determines not to be connected with the other apparatus, and transmitsthe TERMINATE to the other apparatus (step M614).

On the other hand, upon receiving the ADV_IND, the TX1 confirms whethera UUID representing a wireless charge service is included in theADV_IND. Here, as described above, the ADV_IND includes the UUIDrepresenting the wireless charge service. Next, the TX1 refers to thememory 207 and determines whether the transmission source of the ADV_INDmatches the identification information (BD_ADDR) of the RX1 held in thememory 207. Since the ADV_IND in step M612 is transmitted from the RX1,the TX1 determines to be connected to the RX1 that is the transmissionsource of the ADV_IND, and transmits a CONNECT to the RX1 (step M615).Since the transmission source of the CONNECT is the TX1, in this case,the RX1 does not transmit the TERMINATE and maintains the connection.

Note that in some cases, the TX2 receives the ADV_IND transmitted by theRX1. In this case, however, the TX2 holds the BD_ADDR of the RX2existing within the power transmission/reception range in the memory 207but not the BD_ADDR of the RX1. For this reason, the TX2 does nottransmit the CONNECT to the RX1.

After that, the TX1 and the RX1 perform the negotiation concerning theGP using the BLE (out-band communication) (step M616). At this point oftime, the TX1 can use the BLE (out-band communication) for controlcommunication with the RX1 existing within the powertransmission/reception range and therefore sets the allowable maximumvalue of the GP to 100 W. The RX1 also sets the maximum value of the GPto be requested to 100 W. Then, the TX1 and the RX1 perform thenegotiation to determine the GP using the allowable value of the GP andthe requested value of the GP. After that, after processing in thecalibration phase is executed (step M617), in the PT phase, powertransmission to change the battery is performed between the TX1 and theRX1 (step M618). In the PT phase, control data to request toincrease/decrease the transmission power is transmitted from the RX1 tothe TX1. In this example, this is done by the BLE (out-bandcommunication).

When the charge ends, the RX1 transmits the EPT representing a requestto stop power transmission for battery charge to the TX1 by the BLE(out-band communication) (step M619). Upon receiving the EPT, the TX1ends the power transmission for charge. When the power transmission forcharge ends, the RX1 transmits the TERMINATE to the TX1 and disconnectsthe BLE (step M620).

As described above, in this embodiment, each of the power transmissionapparatus and the power receiving apparatus specifies, using in-bandcommunication, whether the partner apparatus is compliant with out-bandcommunication. Each of the power transmission apparatus and the powerreceiving apparatus obtains, using in-band communication, identificationinformation used by the partner apparatus in out-band communication. Inaddition, upon receiving the ADV_IND by the out-band communication, thepower transmission apparatus determines, based on the identificationinformation obtained by the in-band communication, whether to transmitthe CONNECT. Also, upon receiving the CONNECT that is the response tothe ADV_IND, the power receiving apparatus determines, based on theidentification information obtained by the in-band communication,whether to transmit the TERMINATE.

This allows the power transmission apparatus and the power receivingapparatus to perform control communication by the BLE with the powerreceiving apparatus and the power transmission apparatus, which arelocated within the power transmission/reception range, before thetransmission/reception of a power to charge the battery or thenegotiation of the power. When the control communication is performed byout-band communication in this way, a large power can betransmitted/received as compared to a case of in-band communication.

If the partner apparatus is compliant with the BLE but cannot use theBLE (when the BLE Enable bit is “0”), each of the power transmissionapparatus and the power receiving apparatus determines to use notout-band communication but in-band communication. This allows the powertransmission apparatus and the power receiving apparatus to performpower transmission/reception using in-band communication in a case inwhich the BLE is already used by the control unit of a product to whichthe partner apparatus is connected.

Note that in the above-described embodiment, when out-band communicationcannot be executed, the maximum GP allowable in the power transmissionapparatus and the maximum value of the GP requested by the powerreceiving apparatus are set to 15 W. In addition, if the TX1 is a powertransmission apparatus of a version before the version 1.2 of the WPCstandard, the power supplied to the load of the power receivingapparatus is limited to 5 W. On the other hand, depending on the productconnected to the power receiving apparatus, the product is assumed to beunable to operate because of a power shortage in a case of 5 W or 15 W.For example, the load may be a product that does not operate by thepower of the battery and directly receives power supply from the powerreceiving unit 302. In this case, when the power of 5 W or 15 W issupplied, the product may cause an operation error. To avoid such astate, upon determining that out-band communication cannot be used forcontrol communication, the power receiving apparatus may transmit theEPT to the power transmission apparatus. This can prevent aninsufficient power from being supplied by wireless power transmissionand prevent a problem such as an operation error from occurring in theproduct.

On the other hand, also considerable is a case in which the control unitof the product connected to the RX1 controls the BLE (secondcommunication unit 304) of the RX1, and the second communication unit304 operates by the power of the battery 307. In a case in which thebattery remaining amount is not sufficient in such a system (forexample, in a case in which the battery remaining amount is 0) as well,out-band communication cannot be executed. However, in a case in whichthe product operates by the power of the battery, if the batteryremaining amount is not sufficient, the product does not operate, andtherefore, the above-described problem such as an operation error doesnot occur. For this reason, the RX1 may receive a power of 15 W usingin-band communication instead of transmitting the EPT.

Additionally, in the above-described embodiment, the RX1 transmits theGeneral Req (ID), thereby requesting transmission of the BD_ADDR of theTX1. However, the present disclosure is not limited to this. Forexample, of the Specific Requests of the version 1.2.2 of the WPCstandard, a Reserved Packet or Proprietary Packet whose Packet type isundefined may be used for the request. Alternatively, of the GeneralRequests of the version 1.2.2 of the WPC standard, a Reserved Packet orProprietary Packet whose Packet type is undefined may be used for therequest. Also, of the packets of the version 1.2.2 of the WPC standard,a packet other than the Specific Requests and the General Requests maybe used for the request. For example, a Reserved Packet or ProprietaryPacket other than the Specific Requests and the General Requests, whosePacket type is undefined, can be used for the request.

Additionally, in the above description, the RX1 notifies the TX1, usingthe Configuration Packet, that the self-apparatus is compliant withcontrol communication by the BLE. However, the present disclosure is notlimited to this. For example, of the Specific Requests of the version1.2.2 of the WPC standard, a Reserved Packet or Proprietary Packet whosePacket type is undefined may be used to make this notification.Alternatively, of the General Requests of the version 1.2.2 of the WPCstandard, a Reserved Packet or Proprietary Packet whose Packet type isundefined may be used for this notification. Also, of the packets of theversion 1.2.2 of the WPC standard, a packet other than the SpecificRequests and the General Requests may be used for this notification. Forexample, a Reserved Packet or Proprietary Packet other than the SpecificRequests and the General Requests, whose Packet type is undefined, maybe used.

Additionally, in the above description, the BD_ADDR is a Public Addressdefined by the BLE standard and representing the manufacturer of thepower transmission apparatus or the power receiving apparatus or theindividual identification information of the communication circuit(second communication unit) of the BLE. However, the present disclosureis not limited to this. For example, a random number automaticallygenerated by the second communication unit, such as a Random Addressdefined by the BLE standard, may be used. Of the Random Addresses, oneof a Static Device Address, a Resolvable Private Address, and aNon-resolvable Private Address may be used. Here, the Static DeviceAddress is a random number address generated every time the secondcommunication unit (BLE communication circuit) is powered on. TheNon-resolvable Private Address is a random number address generated at apredetermined time interval. The Resolvable Private Address is anaddress generated based on an encryption key exchanged between a Centraland a Peripheral.

Additionally, in the above description, the RX1 transmits the ADV_IND instep M612, and transmits the TERMINATE in response to the CONNECT from aBLE compliant device (for example, the first communication apparatus 121or the TX2) other than the TX1 that has transmitted the BD_ADDR byin-band communication. Instead, in step M612, an ADV_DIRECT_IND definedby the BLE standard and capable of directly designating the BD_ADDR of aBLE compliant device that should transmit the CONNECT may betransmitted. For example, the RX1 transmits the ADV_DIRECT_IND storingthe BD_ADDR of the TX1 in step M612. In this case, only the TX1 with thedesignated BD_ADDR transmits the CONNECT, and the first communicationapparatus 121 does not transmit the CONNECT. This can simplify theconnection processing of the BLE.

Additionally, in this embodiment, an example in which the powerreceiving apparatus is a Peripheral, and the power transmissionapparatus is a Central, as shown in FIG. 1, has been described. However,the power receiving apparatus may be a Central, and the powertransmission apparatus may be a Peripheral. That is, in the processingconcerning the BLE in the above description, the RX1 and the TX1 may beexchanged. For example, to attempt control communication by the BLE withthe RX1, the TX1 activates the BLE of the self-apparatus as theadvertiser, and transmits the ADV_IND in step M612. To attempt controlcommunication by the BLE with the TX1, the RX1 can activate the BLE ofthe self-apparatus as the scanner and receive the ADV_IND from the TX1.If the identification information of the transmission source of theADV_IND corresponds to the BD_ADDR of the TX1 obtained by receiving theTX ID Packet in step M611, the RX1 can transmit the CONNECT to the TX1in step M615. Based on the BD_ADDR of the RX1 obtained by receiving theExtended ID Packet obtained in step M605, the TX1 establishes andmaintains connection by the BLE in accordance with the CONNECT from theRX1. On the other hand, if the CONNECT from an apparatus other than theRX1 is received, the TX1 transmits the TERMINATE to disconnect theestablished BLE connection, thereby rejecting the BLE connection. Notethat in this case as well, in step M612, the TX1 may transmit theADV_DIRECT_IND storing the BD_ADDR of the RX1 received in advance.

Additionally, in the above description, the TX1 or the RX1 determines,using the BLE bit or the BLE Enable bit, whether the partner apparatusis compliant with the BLE or can use the BLE. However, at least one ofthe determinations may be done by a response to a packet that requeststransition from in-band communication to out-band communication and istransmitted by the RX1. In the negotiation phase, the RX1 can use, forthis request, a Reserved Packet or Proprietary Packet whose Packet typeis undefined in the Specific Requests of the version 1.2.2 of the WPCstandard. Alternatively, of the General Requests of the version 1.2.2 ofthe WPC standard, a Reserved Packet or Proprietary Packet whose Packettype is undefined may be used for the request. Also, of the packets ofthe version 1.2.2 of the WPC standard, a packet other than the SpecificRequests and the General Requests may be used for the request. Forexample, a packet that requests out-band communication may newly bedefined using these packets, and upon receiving the ACK from the TX1 asthe response to the packet, the RX1 may determine that the TX1 iscompliant with the BLE and can use the BLE (YES in step S508). Inaddition, upon receiving a NAK that means rejection of the request, theRX1 may determine that the TX1 is not compliant with the BLE or cannotuse the BLE, and may determine to use in-band communication (step S521).In a case in which the TX1 is not compliant with the version A, the TX1transmits a No Data Response (ND Resp) packet representing that therequest cannot be understood or a Not Data Available packet. Hence, uponreceiving the ND Resp packet or the Not Data Available packet, the RX1can determine to use in-band communication because the TX1 is notcompliant with out-band communication (step S521).

Additionally, in the above-described embodiment, the RX1 transmits theBD_ADDR using the Extended ID Packet. When the Extended ID Packetalready defined by the WPC standard is used to transmit the BD_ADDR, thealready defined packet can be used without newly defining a packet inthe version A.

In addition, after the transmission of the ACK in step M607, a TX1 andan RX1 of the version 1.2.2 transition to the negotiation phase andperform the negotiation of the GP. To the contrary, the TX1 and the RX1according to this embodiment perform the BLE connection processing(steps M612 and M615) and then perform a negotiation to determinewhether to set the GP to 15 W or 100 W in accordance with the result ofthe connection processing. At this time, when the maximum value of theGP allowable in the TX1 and that of the GP requested by the RX1 aredetermined, before the negotiation, based on the result of BLEconnection, the necessity of a renegotiation that is performed in a caseof inappropriate GP setting is obviated. As a result, waste of timecaused by such a renegotiation can be reduced. For example, in a case inwhich BLE connection cannot be established after it is determined totransmit a power of 100 W as the result of negotiation, it is necessaryto set the maximum value of the GP to 15 W and perform a renegotiation.However, such a situation can be avoided.

In the above description, an example in which wireless powertransmission complying with the WPC standard is used has been described.However, the power transmission method is not particularly limited. Forexample, a magnetic field resonance method of transmitting a power usingcoupling caused by the resonance of a magnetic field between theresonator (resonance element) of the TX and the resonator (resonanceelement) of the RX may be used. Alternatively, a power transmissionmethod using an electromagnetic induction method, an electric fieldresonance method, a microwave method, a laser, or the like may be used.

Note that the above description has been made using specific technicalterms based on the WPC standard and the BLE standard. However, thepresent disclosure is not limited to this. That is, the presentdisclosure should be interpreted to incorporate a case in which in asystem having the same arrangement as described above, messages of thesame effects are transmitted/received, and the same processes areexecuted. Additionally, in the above-described description, a field usedto transmit specific information is provided in a specified message inthe WPC standard or the BLE standard. However, the present disclosure isnot limited to this. That is, to transmit information of the sameeffect, a message different from that described above may be used. Forexample, in the above description, the information representing whetherthe RX1 is compliant with the BLE or whether the RX1 can execute controlcommunication by the BLE is stored in a specific field in theConfiguration Packet. However, a new message to transmit these pieces ofinformation may be defined. This also applies to the remaining messages.

In addition, the power transmission apparatus and the power receivingapparatus may each be included in, for example, an image input apparatussuch as an image capturing apparatus (a camera or a video camera) or ascanner, or an image output apparatus such as a printer, a copyingmachine, or a projector. Also, the power transmission apparatus and thepower receiving apparatus may each be included in a storage device suchas a hard disk drive or a memory device, or an information processingapparatus such as a personal computer (PC) or a smartphone.

Other Embodiments

Embodiment(s) of the present disclosure can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as(‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2018-074991, filed Apr. 9, 2018 which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A power receiving apparatus comprising: a powerreceiving unit configured to wirelessly receive a power from a powertransmission apparatus; a first communication unit configured to performcommunication of a first method using a first frequency to be used forpower transmission; a second communication unit configured to performcommunication of a second method using a second frequency different fromthe first frequency; and a control unit configured to control the firstcommunication unit and the second communication unit to perform controlcommunication for the power transmission, wherein the control unitcontrols the first communication unit to receive a first signalincluding information representing whether the power transmissionapparatus can execute the control communication by the communication ofthe second method, controls, based on that the information included inthe first signal received by the first communication unit representsthat the power transmission apparatus can execute the controlcommunication by the communication of the second method, the firstcommunication unit to transmit, to the power transmission apparatus, asecond signal to request identification information of the powertransmission apparatus for the communication of the second method andreceive the identification information from the power transmissionapparatus, and determines which one of the first communication unit andthe second communication unit should be used for the controlcommunication, based on the first signal received by the firstcommunication unit and whether the identification information isreceived by the first communication unit.
 2. The apparatus according toclaim 1, wherein the first signal includes, as the informationrepresenting whether the power transmission apparatus, a fieldconfigured to represent whether the power transmission apparatus has afunction of performing the communication of the second method and/or afield configured to represent whether the power transmission apparatusis in a state in which it is possible to perform the communication ofthe second method at a point of time of transmitting the first signal.3. The apparatus according to claim 1, wherein the first signal is aPower Transmitter Capability Packet of a WPC standard.
 4. The apparatusaccording to claim 1, wherein the control unit determines to use thefirst communication unit for the control communication, based on thatthe information represents that the power transmission apparatus cannotexecute the control communication by the communication of the secondmethod.
 5. The apparatus according to claim 1, wherein the control unitcontrols the second communication unit to establish connection andperform the control communication, based on that a request of connectionfrom a transmission source corresponding to the identificationinformation is received by the second communication unit, and not toestablish connection, based on that the request of connection from atransmission source that does not correspond to the identificationinformation is received by the second communication unit.
 6. Theapparatus according to claim 1, wherein the control unit determines touse the first communication unit for the control communication, based onan elapse of a predetermined time without receiving, by the secondcommunication unit, a request of connection from a transmission sourcecorresponding to the identification information.
 7. The apparatusaccording to claim 1, wherein the second signal is a General Requestthat inquires about the identification information in a WPC standard. 8.The apparatus according to claim 1, wherein the control unit controlsthe first communication unit to transmit, to the power transmissionapparatus, a third signal including information representing whether thepower receiving apparatus can execute the control communication by thecommunication of the second method.
 9. The apparatus according to claim8, wherein the third signal includes, as the information representingwhether the power receiving apparatus can execute the controlcommunication by the communication of the second method, a fieldconfigured to represent whether the power receiving apparatus has afunction of performing the communication of the second method and/or afield configured to represent whether the power receiving apparatus isin a state in which it is possible to perform the communication of thesecond method at a point of time of transmitting the third signal. 10.The apparatus according to claim 8, wherein the third signal is aConfiguration Packet of a WPC standard.
 11. The apparatus according toclaim 8, wherein the control unit determines to use the firstcommunication unit for the control communication, based on that aresponse to the third signal is not received from the power transmissionapparatus.
 12. The apparatus according to claim 1, wherein the controlunit controls the first communication unit to transmit, to the powertransmission apparatus, a fourth signal including identificationinformation of the power receiving apparatus in the communication of thesecond method.
 13. The apparatus according to claim 12, wherein thefourth signal is an Extended Identification Packet of a WPC standard.14. The apparatus according to claim 1, wherein the communication of thefirst method is communication complying with a WPC standard, and thecommunication of the second method is communication of Bluetooth LowEnergy.
 15. A power transmission apparatus comprising: a powertransmission unit configured to wirelessly transmit a power to a powerreceiving apparatus; a first communication unit configured to performcommunication of a first method using a first frequency to be used forpower transmission; a second communication unit configured to performcommunication of a second method using a second frequency different fromthe first frequency; and a control unit configured to control the firstcommunication unit and the second communication unit to perform controlcommunication for the power transmission, wherein the control unitcontrols the first communication unit to receive a first signalincluding information representing whether the power receiving apparatuscan execute the control communication by the communication of the secondmethod, and determines which one of the first communication unit and thesecond communication unit should be used for the control communication,based on the information included in the first signal received by thefirst communication unit.
 16. The apparatus according to claim 15,wherein the first signal includes, as the information representingwhether the power receiving apparatus can execute the controlcommunication, a field configured to represent whether the powerreceiving apparatus has a function of performing the communication ofthe second method and/or a field configured to represent whether thepower receiving apparatus is in a state in which it is possible toperform the communication of the second method at a point of time oftransmitting the first signal.
 17. The apparatus according to claim 15,wherein the control unit determines to use the first communication unitfor the control communication, based on that the information representsthat the power receiving apparatus cannot execute the controlcommunication by the communication of the second method.
 18. Theapparatus according to claim 15, wherein the control unit controls thefirst communication unit to transmit, to the power receiving apparatus,a third signal including identification information of the powertransmission apparatus for the communication of the second method, basedon that a second signal to request the identification information isreceived.
 19. The apparatus according to claim 18, wherein the thirdsignal is a Transmitter Identification Packet of a WPC standard.
 20. Theapparatus according to claim 15, wherein the control unit controls thefirst communication unit to receive, from the power receiving apparatus,a fourth signal including identification information of the powerreceiving apparatus in the communication of the second method, andcontrols the second communication unit to transmit a request ofconnection to the power receiving apparatus, based on that a fifthsignal including the identification information of the power receivingapparatus in the communication of the second method is received by thesecond communication unit.
 21. The apparatus according to claim 15,wherein the control unit controls the first communication unit totransmit, to the power receiving apparatus, a sixth signal includinginformation representing whether the power transmission apparatus canexecute the control communication by the communication of the secondmethod.
 22. The apparatus according to claim 15, wherein thecommunication of the first method is communication complying with a WPCstandard, and the communication of the second method is communicationcomplying with a Bluetooth Low Energy standard.
 23. A method ofcontrolling a power receiving apparatus that includes a firstcommunication unit configured to perform communication of a first methodusing a first frequency to be used for power transmission, and a secondcommunication unit configured to perform communication of a secondmethod using a second frequency different from the first frequency, andwirelessly receives a power from a power transmission apparatus, themethod comprising: controlling the first communication unit to receive afirst signal including information representing whether the powertransmission apparatus can execute control communication by thecommunication of the second method; controlling, based on that theinformation included in the first signal received by the firstcommunication unit represents that the power transmission apparatus canexecute the control communication by the communication of the secondmethod, the first communication unit to transmit, to the powertransmission apparatus, a second signal to request identificationinformation of the power transmission apparatus for the communication ofthe second method and receive the identification information from thepower transmission apparatus; and determining which one of the firstcommunication unit and the second communication unit should be used forthe control communication, based on the first signal received by thefirst communication unit and whether the identification information isreceived by the first communication unit.
 24. A method of controlling apower transmission apparatus that includes a first communication unitconfigured to perform communication of a first method using a firstfrequency to be used for power transmission, and a second communicationunit configured to perform communication of a second method using asecond frequency different from the first frequency, and wirelesslytransmits a power to a power receiving apparatus, the method comprising:controlling the first communication unit to receive a first signalincluding information representing whether the power receiving apparatuscan execute control communication by the communication of the secondmethod; and determining which one of the first communication unit andthe second communication unit should be used for the controlcommunication, based on the information included in the first signalreceived by the first communication unit.
 25. A non-transitorycomputer-readable storage medium that stores a program configured tocause a computer provided in a power receiving apparatus that includes afirst communication unit configured to perform communication of a firstmethod using a first frequency to be used for power transmission, and asecond communication unit configured to perform communication of asecond method using a second frequency different from the firstfrequency, and wirelessly receives a power from a power transmissionapparatus to: control the first communication unit to receive a firstsignal including information representing whether the power transmissionapparatus can execute control communication by the communication of thesecond method; control, based on that the information included in thefirst signal received by the first communication unit represents thatthe power transmission apparatus can execute the control communicationby the communication of the second method, the first communication unitto transmit, to the power transmission apparatus, a second signal torequest identification information of the power transmission apparatusfor the communication of the second method and receive theidentification information from the power transmission apparatus; anddetermine which one of the first communication unit and the secondcommunication unit should be used for the control communication, basedon the first signal received by the first communication unit and whetherthe identification information is received by the first communicationunit.
 26. A non-transitory computer-readable storage medium that storesa program configured to cause a computer provided in a powertransmission apparatus that includes a first communication unitconfigured to perform communication of a first method using a firstfrequency to be used for power transmission, and a second communicationunit configured to perform communication of a second method using asecond frequency different from the first frequency, and wirelesslytransmits a power to a power receiving apparatus to: control the firstcommunication unit to receive a first signal including informationrepresenting whether the power receiving apparatus can execute controlcommunication by the communication of the second method; and determinewhich one of the first communication unit and the second communicationunit should be used for the control communication, based on theinformation included in the first signal received by the firstcommunication unit.